Page 21 - Parquet International luglio 2014

Phases of investigation
I examined a part of the floor that had risen up and detached itself from the laying sur- face. In this regard, it is important to note that no dimensional deformation was ob- served on the long side of the single planks (Photo 1). The surfaces were all in perfect planarity, in fact. After one plank was re- moved, the bottom layer was examined and the moisture content (in weight) of the lay- ing surface was measured. I think that this is always a good thing to do, even months later, because a wood floor will not detach unless something has disturbed its stability. I then performed the chemical reaction test also known as the “carbide” test to Standard UNI 10329 dated February 1994. Following this procedure, we triggered a reaction in the compound that we had removed from approx. 6 cm below the laying surface: the result we obtained was a value slightly less than 2%. The result obtained was in line with the usual parameters in the sector and as indicated also in Point 4.2.2.3, Page 4 of Standard UNI 11371 “Screeds for parquet and wood flooring – properties and charac- teristics of performance”. (Photos 2 and 3) In this phase, when the planks were lifted up to permit the extraction of the sample of concrete, we observed the gluing method adopted and the “distribution and the grooving” of the adhesive.
Here we observed the first and the most ev-
ident anomaly: the height of the tops of the grooves in the adhesive left by the spatula used was very low. The first effect of this er- ror is a very poor adhesion of the glue it- self to the wooden plank's bottom layer and vice-versa, especially bearing in mind that in this case, the planks had noteworthy di- mensions (Photos 4 and 5). As I inspected the floor, I noticed that many other sections were in the process of detaching themselves from the laying surface (Photo 6). Another particular to be borne in mind together with the “hollow thudding sounds" given off by single planks was the vertical movement of the respective parts of the floor. No dimen- sional deformation was noticed in any of the single planks, however, and this was docu- mented by the fact that the wood laid onsite checked by electric conductivity instru- mentation provided results only scarcely higher than the maximum value specified by the reference standards. The moisture content measurement method adopted in this case was the one provided by Standard UNI EN 13183-2.
Analysis of the causes
Bearing in mind that our examination was based on what we measured and observed at the site at the moment of inspection, we believe with reasonable certainty the de- tachment of the planks was due to the fol- lowing factors: R
1
2
These photos show the various phases in the investigation
of the floor under dispute
3
6
4
5
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